1. Field of the Invention
The present invention relates to a roller mechanism for generating a plurality of control signals. The control signals may be used for scrolling an image on a computer display in multiple directions.
2. Description of the Prior Art
GUI (graphical user interface) controls have been widely applied to a variety of devices, including computers, telephones, televisions, hand-held devices or the like. For example, U.S. Pat. No. 5,530,455 discloses a pioneering utilization of a roller in a computer input device for scrolling an image on a computer display either in a horizontal and vertical direction. However the scrolling direction is limited to a one specified direction at a time, or the cursor has to be moved to the other scrolling bar such that the computer will verify a desired scrolling direction.
In order to overcome the inconvenience mentioned above, U.S. Pat. No. 6,700,564 discloses a laterally movable roller, thereby providing an adding movement direction. However, this arrangement suffers the disadvantage that the laterally movable roller is difficult to use, prompting a further improvement described in U.S. Patent Publication No. 2003/0025673. The further improvement is that the light emitter and a light receiver used to sense movement are located within a large roller to facilitate manipulation of the roller. While more convenient to use, the input device with the light emitter and receiver within the roller is a relatively costly mechanism, particularly when the input device in which it is used is miniaturized.
Yet another improvement is disclosed in U.S. Patent Publication No. 2004/0174336, which utilizes a ball joint coupled to the center of the roller to enable tilting of the roller with a simpler structure. However, due to the tight narrow tolerance of the combination, the simplified structure has a short life span if the user tilts the roller frequently.